But Posh fought back in memorable fashion with substitute Simpson, Lee and Boyd completing a stunning comeback against Dave Jones' side.
The draw still means Mark Cooper's team enter the New Year at the foot of the table while Cardiff, who were denied their first win at London Road for 23 years, lost precious points in the race for promotion.
The visitors started in style as they looked to erase memories of defeat by the Pilgrims and Whittingham struck a post after four minutes following good work on the right by Chris Burke.
Whittingham found Ledley who placed a well-taken finish into the bottom corner from the middle of the penalty area.
Cardiff's confidence was high and although Peterborough showed signs of encouragement it was soon 2-0 to the visitors.
Whittingham and Ledley combined again, the former's corner from the right which the latter met headed home from the back post.
Classy Bothroyd continued the first half rout with a 34th-minute strike, cutting inside on the right and hammering a shot past a helpless Joe Lewis with his left foot.
Cardiff capped a superb first-half display as Whittingham deservedly got on the scoresheet with a curling 25-yard free-kick.
Cooper made two changes at the break to bolster his midfield and he got the response he craved. Simpson struck from close range, converting Mackail-Smith's pass from the left.
The strike lifted the hosts' and their morale was unaffected by the 62nd-minute departure of goalkeeper Lewis with injury.
Lee met Boyd's cross with a header to set up a nerve-wracking final 22 minutes. Posh had almost completely dominated after the interval and Boyd volleyed home a third in the 89th minute.
All-but the visiting fans among the 9,796 in attendance were simply delirious with delight three minutes later as Simpson levelled from close range.
Cardiff were also left wondering about an injury that led to Bothroyd being carried off in the 77th minute.
Peterborough boss Mark Cooper:
"Our first-half performance was completely unacceptable.
"We didn't get close to Cardiff, we didn't tackle, we didn't head and to be quite honest, we didn't do anything.
"If you don't want to compete, you won't win a football match - whether it is in the local park or the Premier League.
"I didn't say a lot to the players at half-time - in fact, I thought about getting in my car and going home!
"But we changed our shape, changed our personnel and got ourselves back into the game.
"Cardiff probably thought it would be a stroll but we ended up getting a point, but I am still really frustrated that it took us until the second half to start playing.
"If we are capable of scoring four goals against a team chasing promotion in the space of 45 minutes, what could we do if we performed for a whole game?"
Cardiff City boss Dave Jones:
Jones fumes at Cardiff horror show
"The mentality at the moment is not to see out the game and people will say "how did you go to West Brom and Middlesbrough and see it out?", but they thought they'd won it today.
"Against West Brom and Middlesbrough they didn't think they'd won it. They had to battle. Today they didn't do the shift that we demand and expect of them.
"And that's the most disappointing thing for me, by far. I don't berate my players in public, but today they deserve all the berating that can be thrown at them because they let everybody down.
"They let the fans down, they let me down, they let the staff down and more importantly they let themselves down in the second half.
"In the first half it was just one-way traffic. It was pure domination and it is a hard pill for me to swallow."
Live text and stats
Monday, 28 December 2009
01 Lewis (McKeown 62)
04 Morgan yellow card
34 Geohaghan (Simpson 46)
19 Batt yellow card
09 Mclean (Frecklington 46)
02 McNaughton (Quinn 46 yellow card)
09 Bothroyd (Etuhu 77)
44 McCormack (Chopra 70)
Ref: WhitestoneAtt: 9,796
Attempts on target
Attempts off target
90:00+4:47 The referee blows for the end of the match.
90:00+4:02 Corner taken by Chris Burke, Chris Whelpdale makes a brilliant save.
90:00+3:16 Corner taken by Peter Whittingham from the right by-line.
90:00+1:59 GOAL - Josh Simpson:Peterborough 4 - 4 Cardiff Goal scored by Josh Simpson from close range to the bottom right corner of the goal. Peterborough 4-4 Cardiff.
90:00+1:24 Michael Chopra concedes a free kick for a foul on Scott Griffiths. Free kick taken by Charlie Lee.
89:53 Shaun Batt produces a cross.
89:00 GOAL - George Boyd:Peterborough 3 - 4 Cardiff A goal is scored by George Boyd from inside the penalty box to the top right corner of the goal. Peterborough 3-4 Cardiff.
88:40 George Boyd takes a shot. Save by David Marshall.
87:04 Josh Simpson challenges Joe Ledley unfairly and gives away a free kick. Direct free kick taken by David Marshall.
85:39 The ball is swung over by Chris Whelpdale, Anthony Gerrard makes a clearance. Corner from the left by-line taken by Paul Coutts,
Craig Morgan has a headed effort at goal from close in which goes wide right of the goal.
85:22 The ball is delivered by Chris Whelpdale, Anthony Gerrard makes a clearance.
83:56 Free kick awarded for an unfair challenge on Lee Frecklington by Gavin Rae. Direct free kick taken by Paul Coutts.
83:17 Paul Coutts fouled by Michael Chopra, the ref awards a free kick. Craig Morgan restarts play with the free kick.
82:50 The referee blows for offside against Michael Chopra. Free kick taken by James McKeown.
81:51 Shot by Scott Griffiths from a long way out goes over the target.
81:01 Lee Frecklington takes a shot. David Marshall makes a save.
79:46 The ball is crossed by Paul Quinn, James McKeown makes a save.
78:28 Free kick taken by David Marshall.
78:28 Booking Shaun Batt goes into the referee's book.
78:23 Unfair challenge on Anthony Gerrard by Shaun Batt results in a free kick.
76:37 Substitution Jay Bothroyd leaves the field to be replaced by Kelvin Etuhu.
74:06 Chris Whelpdale sends in a cross, Anthony Gerrard makes a clearance. Lee Frecklington takes a shot. Save made by David Marshall.
73:04 Free kick awarded for a foul by Mark Hudson on Craig Mackail-Smith. George Boyd crosses the ball in from the free kick, Adam
Matthews manages to make a clearance.
69:52 Substitution Michael Chopra is brought on as a substitute for Ross McCormack.
69:42 A cross is delivered by George Boyd.
68:19 Free kick awarded for an unfair challenge on Craig Mackail-Smith by Mark Hudson. Free kick crossed by George Boyd, clearance
made by Paul Quinn. Corner taken by George Boyd from the right by-line to the near post, Mark Hudson makes a clearance.
67:36 Assist by George Boyd.
67:36 GOAL - Charlie Lee:Peterborough 2 - 4 Cardiff Charlie Lee finds the back of the net with a headed goal from inside the six-yard box. Peterborough 2-4 Cardiff.
67:29 The ball is sent over by George Boyd,
67:07 Corner from the right by-line taken by George Boyd, clearance made by Mark Hudson.
65:33 The free kick is swung in right-footed by Paul Coutts, clearance by Anthony Gerrard.
65:33 Booking Paul Quinn is booked.
65:25 Foul by Paul Quinn on Shaun Batt, free kick awarded.
64:52 Effort by Lee Frecklington from a long way out goes over the target.
64:08 Gavin Rae gives away a free kick for an unfair challenge on Paul Coutts. Direct free kick taken by Paul Coutts.
61:58 Substitution Joe Lewis goes off and James McKeown comes on.
59:23 The assistant referee signals for offside against Ross McCormack. Direct free kick taken by Scott Griffiths.
58:32 Ross McCormack is flagged offside by the assistant referee. Direct free kick taken by Joe Lewis.
55:03 Unfair challenge on Josh Simpson by Jay Bothroyd results in a free kick. Paul Coutts shoots direct from the free kick.
54:23 The referee blows for offside. Joe Lewis restarts play with the free kick.
53:45 Peter Whittingham produces a cross, clearance by Craig Morgan.
52:37 Shaun Batt produces a right-footed shot from just outside the penalty box that misses to the left of the goal.
52:06 The ball is swung over by Peter Whittingham, Chris Burke takes a shot. Save by Joe Lewis.
51:00 Assist by Craig Mackail-Smith.
51:00 GOAL - Josh Simpson:Peterborough 1 - 4 Cardiff Josh Simpson finds the back of the net with a goal from inside the six-yard box to the bottom left corner of the goal. Peterborough
48:46 Free kick awarded for an unfair challenge on Jay Bothroyd by Josh Simpson. Jay Bothroyd takes the direct free kick.
46:27 Anthony Gerrard challenges Craig Mackail-Smith unfairly and gives away a free kick. Direct free kick taken by Paul Coutts.
45:24 Free kick awarded for a foul by Craig Mackail-Smith on Mark Hudson. Free kick taken by Mark Hudson.
45:01 The second half has started.
45:01 Substitution Josh Simpson joins the action as a substitute, replacing Exodus Geohaghon.
45:01 Substitution Lee Frecklington joins the action as a substitute, replacing Aaron Mclean.
45:01 Substitution Paul Quinn comes on in place of Kevin McNaughton.
45:00+1:59 The ref blows to signal half-time.
43:46 Craig Morgan gives away a free kick for an unfair challenge on Ross McCormack. Shot comes in from Ross McCormack from the
41:27 The ball is delivered by George Boyd, clearance made by Kevin McNaughton.
40:37 Paul Coutts takes a shot. David Marshall makes a save.
39:05 Charlie Lee has an effort at goal from just outside the box which goes wide of the right-hand upright.
38:47 Free kick awarded for an unfair challenge on Shaun Batt by Peter Whittingham. Chris Whelpdale takes the free kick.
37:11 GOAL - Peter Whittingham:Peterborough 0 - 4 Cardiff Free kick scored by Peter Whittingham from long range to the top right corner of the goal. Peterborough 0-4 Cardiff.
36:28 Unfair challenge on Jay Bothroyd by Charlie Lee results in a free kick.
35:04 Craig Morgan gives away a free kick for an unfair challenge on Jay Bothroyd. Anthony Gerrard restarts play with the free kick.
33:13 GOAL - Jay Bothroyd:Peterborough 0 - 3 Cardiff Jay Bothroyd finds the back of the net with a goal from the edge of the penalty box to the bottom left corner of the goal.
Peterborough 0-3 Cardiff.
31:23 Booking Craig Morgan booked for unsporting behaviour.
29:26 Shot from just outside the area by George Boyd misses to the left of the target.
28:31 Aaron Mclean fouled by Mark Hudson, the ref awards a free kick. The free kick is delivered right-footed by Paul Coutts from
right channel, clearance made by Gavin Rae.
27:09 Jay Bothroyd is caught offside. Joe Lewis restarts play with the free kick.
24:51 Jay Bothroyd challenges Exodus Geohaghon unfairly and gives away a free kick. Free kick taken by Joe Lewis.
22:42 Assist on the goal came from Peter Whittingham.
22:42 GOAL - Joe Ledley:Peterborough 0 - 2 Cardiff Joe Ledley scores a headed goal from inside the six-yard box. Peterborough 0-2 Cardiff.
22:08 Centre by Chris Burke, clearance by Exodus Geohaghon. Corner taken left-footed by Peter Whittingham from the right by-line,
19:51 George Boyd sends in a cross, Joe Ledley gets a block in.
19:36 The ball is delivered by Joe Ledley, save made by Joe Lewis.
18:40 Foul by Shaun Batt on Kevin McNaughton, free kick awarded. David Marshall takes the direct free kick.
16:37 The ball is delivered by Kevin McNaughton, clearance by Craig Morgan.
12:41 Shaun Batt challenges Jay Bothroyd unfairly and gives away a free kick. The free kick is delivered left-footed by Peter Whittingham
from right channel.
10:45 Chris Burke sends in a cross.
9:52 The referee blows for offside. Joe Lewis restarts play with the free kick.
8:12 Centre by Shaun Batt, clearance by Mark Hudson. Charlie Lee has an effort from just inside the box that misses to the left
of the goal.
7:41 Exodus Geohaghon fouled by Jay Bothroyd, the ref awards a free kick. Direct free kick taken by Scott Griffiths.
5:13 Assist by Peter Whittingham.
5:13 GOAL - Joe Ledley:Peterborough 0 - 1 Cardiff Joe Ledley fires in a goal from inside the penalty area to the bottom right corner of the goal. Peterborough 0-1 Cardiff.
3:14 The ball is swung over by Ross McCormack, Peter Whittingham produces a right-footed shot from just inside the box and strikes
2:09 The referee blows for offside. Direct free kick taken by David Marshall.
1:01 Ross McCormack challenges Chris Whelpdale unfairly and gives away a free kick. Joe Lewis takes the direct free kick.
0:18 Gavin Rae concedes a free kick for a foul on Charlie Lee. Exodus Geohaghon restarts play with the free kick.
0:00 The game gets underway.
Live text and data provided by The Press Association.
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